1. Field of the Invention
The present invention relates to a waterproof shoe construction and more particularly, to a waterproof liner for a shoe.
2. Related Art
Most shoe uppers are manufactured of leather or textile material. If the material is not specially treated, it will easily allow water to penetrate it. Such penetration causes the shoe upper to become wet, which in turn can cause the wearer's sock and eventually the wearer's foot to become wet. Walking in a wet shoe is not only uncomfortable, it can cause foot ailments such as blisters to occur.
To remedy this, it is common to apply a waterproof material such as oil, wax, latex, rubber and/or other waterproofing substance to the interior or exterior of the shoe upper. It is also common to manufacture waterproof shoes from rubber or plastic. While these materials do cause the shoe to be waterproof, they do not allow the wearer's foot inside the shoe to breathe. As a result, the foot may perspire causing the foot, the wearer's sock, and eventually even the shoe upper to become wet. As noted above, walking in a wet shoe is quite uncomfortable and unhealthy.
Recent attempts have been made to manufacture shoes which incorporate a liner made of a material which is impervious to water, yet pervious to water vapor. One example is found in U.S. Pat. No. 4,599,810 to Sacre, which is now U.S. Pat. No. Re. 34,890. This patent discloses the use of a sock-like inner lining made of GORE-TEX.RTM. material a composite including a layer of polytetrafluoroethylene (PTFE) manufactured by W. L. Gore & Associates, Newark, Del. This material which is inserted into the shoe upper during the manufacturing process. The lining is secured to the upper by stitching along the top or ankle opening of the shoe. The lining is otherwise unattached to the shoe upper.
The lining disclosed in the Sacre patent does generally eliminate the problems noted above. However, because the lining is sock-like and forms a complete enclosure around the wearer's foot, the lining uses more waterproof material than is necessary to waterproof the shoe. As GORE-TEX.RTM. material is expensive, the resultant cost to manufacture a shoe incorporating the Sacre technology is quite high.
Therefore, the need exists for a comfortable, waterproof shoe construction which is easy and less expensive to manufacture than existing shoe constructions.